1. Field of the Invention
The present invention relates to a power-supplying device for a sliding structure such as a sliding door for constantly supplying power for such as auxiliaries in the sliding structure.
2. Description of the Related Art
FIGS. 7 and 8 show an embodiment of a conventional power-supplying device 40 for a sliding door. Such a power-supplying device is, for example, disclosed in Japanese published patent application No. 2001-354085.
This power-supplying device 40 is installed on a sliding door 1 of a vehicle. This power-supplying device 40 includes a protector 142 that consists of a base receiving a wiring harness 143 and a cover (not shown) made of synthetic resin, and a metallic flat spring 144 mounted on the protector 142 and urging the wiring harness 143 upward.
The protector 142 consists of a substantially semicircular part receiving the wiring harness 143, and a slim extension part extending backward, and includes a vertical substrate 149, a curved peripheral wall 150 extending along a top of the substrate 149, a lower oblong opening 145 for getting out the wiring harness, and a front opening 151.
The protector 142 is interposed vertically between a metallic door panel 152 and a door trim made of synthetic resin (not shown). The wiring harness 143 is bent horizontally at the lower opening 145, arranged in a vehicle body 147, held by a holder (not shown) near a step 148, and arranged in the sliding door through the front opening 151 so that the wiring harness 143 is connected to auxiliaries at the door and the wiring harness with connectors to constantly supply power.
The wiring harness 143 is made of a plurality of electric wires covered by a resilient corrugate tube made of synthetic resin. The corrugate tube is a tube having alternate circular furrows and ridges, and extended from the front opening 151 of the protector 142 to a harness holder at the vehicle body 147.
As shown in FIG. 7, the sliding door 1 is almost fully closed, and the wiring harness 143 is pulled backward and bends the flat spring 144 downward. When the sliding door 1 is half-open, the flat spring 144 absorbs a slack of the wiring harness 143 by urging the wiring harness 143 upward. As shown in FIG. 8, when the sliding door 1 is almost fully open, the wiring harness 143 is pulled forward while bending the flat spring 144 downward.
However, according to a conventional structure described above, because the flat spring 144 urges upward the wiring harness 143 to absorb the slack, a height of the protector 142 should be large in particular when an open/close stroke of the sliding door 1 is large. Therefore, there is a problem that a space for arranging the auxiliaries and the parts becomes small. There is another problem that a cost of the power-supplying device becomes high because the device needs a metallic flat spring 144, brackets for fixing the flat spring 144 and the like. There is another problem that a lot of time is required for fixing the flat spring 144.
Therefore, a power-supplying device disclosed in Japanese published patent application No. 2005-20895 has no flat spring for preventing the protector from upsizing. Rigidity (spring force) of the wiring harness opens the loop of the wiring harness by the harness-guiding member. Thus, the height of the protector can be set lower than that of the conventional protector. Further, a space for arranging the parts in the sliding door can be large, and a flexibility of arranging the parts in the sliding door can be increased.
However, the power-supplying device disclosed in Japanese published patent application No. 2005-20895 needs a resilient member such as a spring for urging downward a second guiding roller of the harness-guiding member. Because the resilient member is contracted when the sliding door is fully open, pulling force for the wiring harness increases. Therefore, a snapping of the wire in the wiring harness may occur. Further, structures for fixing and sliding the guiding rollers of the harness-guiding member are required, so that the structure of the power-supplying device becomes complex, the cost of the power-supplying device is increased, and assembling process becomes hard.
Accordingly, an object of the present invention is to provide a power-supplying device for a sliding structure that allows the structure to be simple, reduces loads of the wiring harness, and allows the protector to be downsized.